The present invention relates to a new and improved construction of a release mechanism for a valve of a fire extinguishing installation employing a linearly movable element which, upon release of a pre-stressed or biased spring, is moved out of a rest position and by virtue of its movement opens the valve.
Both in the case of fire extinguishing installations employing individual flasks or containers housing a suitable fire extinguishing medium or substance and arranged near the object to be protected, and equally, in the case of systems having a centrally arranged battery of flasks or containers housing the fire extinguishing substance, the individual flasks or containers or the like are retained closed by so-called flask valves, in order to prevent undesirable escape of the fire extinguishing medium or substance, for instance CO.sub.2, halon (halogenated hydrocarbons), dry extinguishing powder, foam or water, into the pipe or conduit system. In the event of a fire the valves are opened manually or controlled by an automatic fire alarm system, and the infeed of the fire extinguishing substance is accomplished through the pipe system or the like to the outlet nozzles located at the site of the fire.
It is known to the art to employ control devices in order to open the valves and which contain a linearly movable element, typically for instance a plunger or a pin which, when released, presses against an appropriate part of the valve and thus causes opening of the valve. The control operation can be accomplished, by way of example, mechanically, pneumatically or electrically.
It is already known to employ a pre-stressed or biased spring in order to move the plunger. The spring is released, during the actuation or release operation, for instance electromagnetically. The energy stored in the spring is released and transmitted to the plunger. What is disadvantageous with this system is that the control function only can be carried out in one manner. In order to render possible other types of control functions there are required expensive and complicated auxiliary systems, often utilizing their own energy storages, which, in turn, are susceptible to disturbance and therefore must be additionally monitored.
A further drawback of heretofore known control techniques is that it is not possible, or only possible to a limited degree, to check the same as to their functional reliability. Also, in many control devices there are absent monitoring elements for supervising the requisite operating state and which are needed to obtain a faultless functionality of the fire extinguishing installations, for instance position switches which report to a central signal station the actuation or release of the valve.
In German petty Pat. No. 1,780,878 there is taught to the art a valve actuation device wherein the linear movement needed for actuating a valve is produced by the utilization of two ball pressure plates. These ball pressure plates are retained at a certain spacing relative to one another by balls. Further, these ball pressure plates can be turned relative to one another, whereby the balls can latch or cam into recesses or notches of the ball pressure plates, there thus being reduced the spacing between such plates, and consequently, there being accomplished actuation of the valve.
Similar equipment for translating a rotational movement into a linear movement has been disclosed in U.S. Pat. No. 2,943,496, granted July 5, 1960.
These prior art devices are however associated with the drawback that, while there is reduced the force needed for actuating the valve, nonetheless such force must be formed directly upon actuation of the valve. With the state-of-the-art release mechanisms this force is transmitted by means of an actuation knob or lever to the release mechanism. The elastic elements which are provided serve, to the extent that they are not components of the valve mechanism, only for retaining linearly movable release elements in their rest position. However, in the case of fire extinguishing devices the required expenditure of force has not been sufficiently reduced since, particularly in the case of an automatic release operation, the actuation of the valve must be accomplished with absolute certainty.